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This year it has been three years since SINQ went back into operation after a major neutron guide upgrade. The work on the neutron guides had been completed literally a day before the start of the pandemic lockdown, and SINQ started to produce neutrons again in the summer of 2020. With many of the other neutron facilities in the world undergoing upgrades or being temporary shut down, SINQ emerged as a reliable and crucial pillar providing neutrons to the European scientific community. |
Michel Kenzelmann
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In 2021 and 2022, SINQ became as popular as never before as the oversubscription rate reached the highest values ever for SINQ.
As a national source, SINQ primarily has the goal to serve Swiss scientists, but two new foreign partners in addition to DanScatt from Denmark now also contribute: IFE of Norway and LLB of France both invest in neutron instrumentation at SINQ and help operating instruments at SINQ in order to serve their national communities at home. Such collaborations come with added benefits such as increased scientific exchange and a tighter international network. This mode of access may well prove attractive for national user communities from elsewhere as well.
Michel Kenzelmann
on behalf of the Laboratory for Neutron Scattering and Imaging, NUM Division |
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Next proposal submission deadlines
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A call for SLS proposals will be announced towards the end of the SLS 2.0 upgrade project. An overview of all proposal submission deadlines of the PSI facilities can be found here.
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X-ray tomography helps understand how the heart beats
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SLS — Dynamic structural characterization of the cardiac cycle with tomographic microscopy
How the heart works is well understood on the organ level, but less so on a cellular level. Researchers at the TOMCAT beamline of SLS have now introduced phase-contrast tomographic X-ray imaging as a promising new approach to studying the organ. The key was a specially designed perfused isolated heart system — a so-called Langendorff system — which makes it possible to keep a heart beating after it has been removed from the circulatory system of the donor (in this case, a rat). Making this system compatible with tomographic microscopy opens up the intriguing possibility of leveraging the advantages of multiscale imaging: imaging cellular structure as well as the entire heart. With this capability at hand, the team studied for the very first time the heart in action as it beats, at an unprecedented 10.6 μm spatial resolution and 1 ms temporal resolution. The work should pave the way to detailed investigations into how the heart beats on a cellular level, and to understanding the effect of disease and drugs on the cardiac cycle.
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Further optimising car brakes
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SINQ — Visualisation of microscopic movements of brake callipers using neutron imaging
Human lives depend on brakes. They need to grip quickly and return to their resting position immediately once the brake pedal is released. If they do not return fully, energy losses may occur. This is not noticeable to the driver and does not affect the function of the brake. It can, however, increase a vehicle’s carbon footprint. PSI researchers and employees of ANAXAM and the industrial partner Audi Sport have been exploring this phenomenon. They used neutrons from SINQ to look inside a brake calliper, thereby demonstrating a way of visualising and optimising the movement of the brake pistons. The project is a fine example of how scientific know-how and competencies can further improve a product that has already proven itself in series production. Audi Sport has further optimised the operation of the brake pistons, such that the clearance of the pistons has now been slightly increased when viewed under the neutron beam — meaning that the brake pads separate more reliably from the brake disc when the brakes are released.
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Unconventional superconductivity found in kagome metal
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SμS — Tunable unconventional kagome superconductivity in charge ordered RbV₃Sb₅ and KV₃Sb₅
A year ago, a group of researchers led by PSI physicists detected evidence of time-reversal symmetry-breaking charge order in a kagome metal. This observation can hint towards unconventional superconductivity — a highly desirable trait — but actual evidence that the material exhibited such behaviour was lacking. In a new study, the team now provides direct evidence to make the link between the unusual charge order they observed in RbV3Sb5 and KV3Sb5 and unconventional superconductivity. They did this by utilizing pressure-tuned and ultra-low temperature muon spin spectroscopy at SμS, which allowed them to combine the observations of nodal superconducting pairing and a small superfluid density at ambient pressure — which in turn displays an unconventional dependence on the superconducting critical temperature. These results point to unprecedented tunable nodal kagome superconductivity competing with time-reversal symmetry-breaking charge order and offer unique insights into the nature of the pairing state.
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SwissFEL — Double bunch operation
Among the normal-conducting linac-based light sources, SwissFEL has the unique capability to simultaneously serve two separate undulator lines — Aramis and Athos — up to the full machine repetition rate of 100 Hz using the so-called double bunch operation mode. In this mode, two electron bunches spaced 28 ns apart are extracted from the cathode by two laser pulses with individually controlled repetition rates. In this way, the experiment throughput can be increased with modest additional investment. The machine now routinely operates in this mode and the scheme has demonstrated excellent reliability and stability, as the SwissFEL team reports in a recent publication. Their measurements demonstrate that the separation of the two closely spaced electron bunches does not degrade the FEL performance — but it does introduce some limitations in the setup of the two beamlines. The next step will be to explore possibilities to further increase the efficiency of the facility by extending the scheme to three or even four bunches.
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Heavyweight leptons probe lightweight samples
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CHRISP — Muonic atom spectroscopy with microgram target material
In muonic atom spectroscopy, X-rays are analysed that are emitted after the capture of a negative muon by a nucleus during the cascade down into the ground state. The high mass of the muon compared to that of an electron and the correspondingly high sensitivity of the muonic X-rays to details of the nuclear structure enables high-precision measurements of nuclear charge radii. So far targets of at least a few hundred milligram were needed for muonic atom spectroscopy, but over the past years the muX collaboration has developed a novel method enabling such measurements with targets that are only available in microgram quantities, for example highly radioactive elements. In a recent publication, the method and apparatus are described in detail, and the results of a first measurement with a 5-μg gold target are presented. In the meantime, the method was successfully applied also for a measurement of 248Cm, the heaviest nucleus ever probed with muons, and a measurement of 226Ra is due to follow later this year.
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4th PSI Condensed Matter Summer Camp 2023 - Registration is open
The PSI Summer Camp 2023 with the title "2D Materials: insights and opportunities at large scale facilities" will take place at the Lyceum Alpinum in Zuoz, located in the mountainous area of Switzerland, from 6 August through Friday 11, 2023.
The PSI Summer Camp has the goal of providing a forum for leading scientists to meet and discuss fundamental aspects and open questions of current scientific interest. It follows a more than 20-year tradition to hold condensed matter schools at the Lyceum Alpinum in Zuoz, which provides a lively and informal environment for scientific discussions.
The talks will cover introductions to the research fields, an overview of the current research frontier and also recent research highlights of the speakers. The camp should thus be of high interest to PhD students and established scientists alike. There will be the possibility for PhD students and post-doctoral fellows to present their work in a poster session.
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News from the user facilities
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SLS: A hardware-accelerated data-acquisition system for kilohertz pixel-array X-ray detectors
The SLS upgrade SLS2.0 will enable unique experimental capabilities. The further increase in source brilliance calls at the same time for continuous development of detectors and readout systems operated at high frame rates.
A team led by PSI researchers has now developed a new dedicated detector-readout system, which they named Jungfraujoch, that can handle a continuous data stream of 17 GB per second from a 2-kHz JUNGFRAU 4-megapixel (4M) detector, so that the 4M detector can be operated with macromolecular crystallography beamlines. In performance tests, rates of 30 GB per second were handled successfully, indicating that the operation of even larger and faster detectors will be achievable in the future.
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SINQ: How to squash things carefully
Over the past decade, uniaxial pressure has been established as a versatile control parameter for tuning the properties and behaviours of quantum materials. But applying uniaxial pressure (or, strain) in a controlled manner is extremely difficult in practice. Good news for experimentalists comes now from the Laboratory for Neutron and Muon Instrumentation, who have built a new pressure cell that is based on simple operating principles and can generate forces up to 200 N in both compressive and tensile configurations.
Moreover, thanks to feedback control the system can be operated in a continuous-pressure mode as the temperature is changed. The cell was developed in collaboration with colleagues in Switzerland, Sweden and Germany, with the goal of making the system transferable between various instruments and multiple cryostats, with simple and exchangeable adapters.
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SwissFEL/SμS: SNSF Starting Grants for Kirsten Schnorr and Zurab Guguchia
The PSI scientists Kirsten Schnorr and Zurab Guguchia have each been awarded a prestigious SNSF Starting Grant from the Swiss National Science Foundation (SNSF), amounting to 3.1 million Swiss francs in total for five years. Kirsten Schnorr is the lead scientist of the SwissFEL Maloja experimental station. In her project entitled “Ultrafast X-ray-induced chemistry of solvated nanoparticles and molecules”, she aims to specifically trigger and track chemical reactions in dissolved nanoparticles.
Zurab Guguchia is a senior scientist in the Laboratory for Muon Spin Spectroscopy at PSI. In his project “Unconventional correlated quantum phases of layered materials”, he will exploit the state-of-the-art instrumentation at the large-scale facilities of PSI (muons, neutrons, X-rays) to explore the often mysterious quantum behaviour of layered materials.
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CHRISP: Users Meeting BV54
The 54th edition of the CHRISP user meeting took place from 23 to 25 January 2023. Following a closed half-day on Monday with in-depth status reviews of the Mu3e, n2EDM, MEG II, and MUSE experiments, the Open CHRISP Users Meeting took place on Tuesday. After two years of remote users meetings, we were delighted to welcome again an audience of about 150 users in the auditorium.
On the agenda were presentations on the status of the IMPACT project, new proposals, letters of intent, and selected progress reports. Interesting discussions were sparked by the new projects in the areas of measurements of muonic atoms, the muon electric dipole moment, and the neutron lifetime. On Wednesday afternoon, the chairman of the committee communicated results of the committee internal meetings as oral feedback and recommendations to the projects. As usual, written minutes of the meetings will be publicly available in due course.
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